feat(ai-term): M-SPC cycles attached agents, M-S-SPC cycles all

M-SPC now steps only through attached agents (the ones with a live
on-screen buffer), so the fast chord stays among what's already up.
M-S-SPC steps through all active agents and attaches a detached tmux
session when it lands on one, which is what M-SPC used to do.

I moved the shared step logic into cj/--ai-term-step-among and added
cj/--ai-term-attached-agent-dirs to filter the queue to attached
buffers. I bound both chords globally and in eat-semi-char-mode-map so
they work from inside an agent buffer. C-; a n keeps cycling all.

2 files changed, 68 insertions, 6 deletions

diff --git a/tests/test-ai-term--attached-agent-dirs.el b/tests/test-ai-term--attached-agent-dirs.el
new file mode 100644
index 00000000..bdd69544
--- /dev/null
+++ b/tests/test-ai-term--attached-agent-dirs.el
@@ -0,0 +1,58 @@
+;;; test-ai-term--attached-agent-dirs.el --- Tests for cj/--ai-term-attached-agent-dirs -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; The queue `cj/ai-term-next-attached' (M-SPC) steps through: project dirs
+;; with a live agent BUFFER only -- attached sessions.  Unlike
+;; `cj/--ai-term-active-agent-dirs', detached tmux sessions with no Emacs
+;; buffer are excluded; those are reachable only via `cj/ai-term-next'
+;; (M-S-SPC).  Candidates / buffers / sessions are mocked so the enumeration
+;; logic is exercised without a real tmux server.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'ai-term)
+
+(ert-deftest test-ai-term--attached-agent-dirs-excludes-detached ()
+  "Normal: only dirs with a live buffer are attached; a detached session is
+excluded even though it is active."
+  (let ((buf (get-buffer-create (cj/--ai-term-buffer-name "/p/alpha"))))
+    (unwind-protect
+        (cl-letf (((symbol-function 'cj/--ai-term-candidates)
+                   (lambda (&rest _) '("/p/alpha" "/p/beta" "/p/gamma" "/p/delta")))
+                  ((symbol-function 'cj/--ai-term-agent-buffers)
+                   (lambda (&rest _) (list buf)))
+                  ((symbol-function 'cj/--ai-term-live-tmux-sessions)
+                   (lambda (&rest _) (list (cj/--ai-term-tmux-session-name "/p/gamma")))))
+          ;; alpha attached (buffer), gamma detached (session): only alpha.
+          (should (equal '("/p/alpha") (cj/--ai-term-attached-agent-dirs))))
+      (kill-buffer buf))))
+
+(ert-deftest test-ai-term--attached-agent-dirs-multiple-sorted ()
+  "Normal: multiple attached dirs come back sorted by agent buffer name."
+  (let ((a (get-buffer-create (cj/--ai-term-buffer-name "/p/delta")))
+        (b (get-buffer-create (cj/--ai-term-buffer-name "/p/alpha"))))
+    (unwind-protect
+        (cl-letf (((symbol-function 'cj/--ai-term-candidates)
+                   (lambda (&rest _) '("/p/alpha" "/p/beta" "/p/delta")))
+                  ((symbol-function 'cj/--ai-term-agent-buffers)
+                   (lambda (&rest _) (list a b)))
+                  ((symbol-function 'cj/--ai-term-live-tmux-sessions)
+                   (lambda (&rest _) nil)))
+          (should (equal '("/p/alpha" "/p/delta") (cj/--ai-term-attached-agent-dirs))))
+      (kill-buffer a)
+      (kill-buffer b))))
+
+(ert-deftest test-ai-term--attached-agent-dirs-empty-when-only-detached ()
+  "Boundary: sessions exist but no live buffers -> no attached dirs."
+  (cl-letf (((symbol-function 'cj/--ai-term-candidates) (lambda (&rest _) '("/p/solo")))
+            ((symbol-function 'cj/--ai-term-agent-buffers) (lambda (&rest _) nil))
+            ((symbol-function 'cj/--ai-term-live-tmux-sessions)
+             (lambda (&rest _) (list (cj/--ai-term-tmux-session-name "/p/solo")))))
+    (should (null (cj/--ai-term-attached-agent-dirs)))))
+
+(provide 'test-ai-term--attached-agent-dirs)
+;;; test-ai-term--attached-agent-dirs.el ends here
diff --git a/tests/test-ai-term--keybindings.el b/tests/test-ai-term--keybindings.el
index 6f7f53a5..8b1f8fa5 100644
--- a/tests/test-ai-term--keybindings.el
+++ b/tests/test-ai-term--keybindings.el
@@ -33,14 +33,18 @@
   (should (eq (keymap-lookup cj/custom-keymap "a") cj/ai-term-keymap)))
 
 (ert-deftest test-ai-term-next-bound-to-meta-space-globally ()
-  "Normal: M-SPC runs `cj/ai-term-next' (the fast swap chord)."
-  (should (eq (lookup-key (current-global-map) (kbd "M-SPC")) #'cj/ai-term-next)))
+  "Normal: M-SPC runs `cj/ai-term-next-attached' (cycle attached only) and
+M-S-SPC runs `cj/ai-term-next' (cycle all, including detached)."
+  (should (eq (lookup-key (current-global-map) (kbd "M-SPC")) #'cj/ai-term-next-attached))
+  (should (eq (lookup-key (current-global-map) (kbd "M-S-SPC")) #'cj/ai-term-next)))
 
 (ert-deftest test-ai-term-meta-space-bound-in-eat-semi-char-mode-map ()
-  "Normal: M-SPC is bound in `eat-semi-char-mode-map' so swap works inside an
-agent.  EAT forwards unbound keys to the pty, so the bind is what lets it reach
-Emacs -- no ghostel-style exception list or rebuild is needed."
-  (should (eq (keymap-lookup eat-semi-char-mode-map "M-SPC") #'cj/ai-term-next)))
+  "Normal: both swap chords are bound in `eat-semi-char-mode-map' so they work
+inside an agent.  EAT forwards unbound keys to the pty, so the bind is what lets
+them reach Emacs -- no ghostel-style exception list or rebuild is needed.  M-SPC
+cycles attached only; M-S-SPC cycles all."
+  (should (eq (keymap-lookup eat-semi-char-mode-map "M-SPC") #'cj/ai-term-next-attached))
+  (should (eq (keymap-lookup eat-semi-char-mode-map "M-S-SPC") #'cj/ai-term-next)))
 
 (ert-deftest test-ai-term-f9-family-removed-globally ()
   "Regression: the old F9 family no longer binds the ai-term commands globally."